Kovács (2012) Acta Zoologica Academiae Scientiarum Hungaricae

Kovács, Zs. E. (2012): Dispersal history of an invasive rodent in Hungary – subfossil finds of Rattus rattus. Acta Zoologica Academiae Scientiarum Hungaricae 58 (4): 379–394.

Abstract
The origins of the black rat Rattus rattus can be placed in the Indian Peninsula and its occurrence in Europe is a result of a westward expansion. Based on archaeozoological finds, this rodent came into the Mediterranean and other parts of Europe before the Roman Period, as a commensal species associated with trade, although it was also introduced in many other parts of the continent during that time. After a depression in the population there is an increase in number of rat finds dating to the 11th century in Europe. The same tendency was observed in Hungary. The earliest rat remains in the country were recovered from sites dated to the Roman period (3–4th century AD) from inside and outside the territory of the Empire as well. Remains outside the limes (the border of the empire running along the right bank of the Danube) indicate that the Danube River did not pose a barrier in the expansion of rats. Records from the Roman period were followed by a gap of ca. 1000 years when the appearance of black rat was detected again at medieval Hungarian sites (from the 14th century onwards) reaching large numbers at sites dated to the Ottoman period (16–17th century).


Keywords
Hungary, archaeozoology, black rat, expansion routes, flotation

Purger et al. (2012) Acta Zoologica Academiae Scientiarum Hungaricae

Purger, J. J., Kurucz, K., Csuka, Sz. and Batáry, P. (2012): Do different plasticine eggs in artificial ground nests influence nest survival? Acta Zoologica Academiae Scientiarum Hungaricae 58 (4): 369–378.


Abstract
In order to understand the role of plasticine eggs in nest predation studies, altogether 78 ground nests were monitored in a large wheat field near to Pécs (southern Hungary) in June 2006. Two eggs were placed in each of the artificial nests, comprising, in an alternating sequence, quail + quail, quail + natural colour plasticine, and quail + white lime coloured plasticine eggs. During one week 65.4% of the artificial nests were depredated. When the damage or disappearance of any of the eggs was considered as a predation event, the daily survival rates of nest containing only two quail eggs was higher than of nests with quail and natural plasticine eggs and significantly higher than of nests with quail and white coloured plasticine eggs. When considering predation to real eggs only, the results remained similar, however, the significant difference in survival rates of the two nest types with different plasticine eggs disappeared. Simultaneously with the nest predation experiments, 78 small mammal live traps were set up in the wheat field and operated for 7 nights. The capture success of traps baited with quail egg was 9.9%, with natural plasticine egg 15.4%, and with white coloured plasticine egg 23.1%, but only a marginal significant difference was found between daily survival rates of quail vs. white coloured plasticine eggs. Natural, but especially white coloured plasticine eggs resulted in an increased predation rate, therefore we suggest that in artificial ground nest experiments nest should be considered to be predated only when the real egg is damaged or disappeared.


Keywords
Coturnix coturnix, nest predation, small mammals, live traps, Hungary

Plaiasu et al. (2012) Acta Zoologica Academiae Scientiarum Hungaricae

Plaiasu, R., Vörös, J. and Bancila, R.(2012): Fluctuating asymmetry as a tool in identifying population stress in Hungarian populations of Bombina bombina, B. variegata and their hybrids. Acta Zoologica Academiae Scientiarum Hungaricae 58 (4): 361–368.

Abstract
Hybridization can occur under natural conditions among well-differentiated species and may affect the developmental stability of hybrids. In the present study, we investigated the effect of interspecific hybridization between Bombina bombina and B. variegata on fluctuating asymmetry (FA) of forelimb, femur, tibia and foot. The hybrids did not show higher levels of FA compared to the parental populations for either investigated traits. This suggested that the effect of hybridization on FA in the analyzed traits is negligible or overwhelmed by other factors. A significantly increased FA was found in the B. bombina populations when compared to B. variegata, which can be attributed to low pressure of natural selection in these populations.


Keywords
interspecific hybridization, Bombina, fluctuating asymmetry

Cseresnyés & Csontos (2012) Acta Botanica Croatica

Imre Cseresnyés, Péter Csontos (2012): Soil seed bank of the invasive Robinia pseudoacacia in planted Pinus nigra stands. Acta Botanica Croatica 71 (2): 249–260.


Abstract
Pinus nigra and Robinia pseudoacacia are exotic trees used for afforestation in Hungary. Pinus nigra was non-invasive, howeverR. pseudoacacia escaped from cultivation and invaded several vegetation types including pine plantations. It has recently been planned to cut P. nigra plantations and replace them by native tree stands, especially in nature reserves. The scattered presence of R. pseudoacacia specimens in pine stands might place constraints on planned tree replacement because of their vegetative resproutingand recolonization from an established seed bank. The aim of this study was to investigate the soil seed bank under the canopy of solitary R. pseudoacacia specimens found in P. nigra plantations. Altogether 250 soil samples were collected from the 0–6 and 6–12 cmsoil layers under solitary Robinia trees of varying ages (with basal areas between 62.4 and 1089.3 cm2). Seeds were separated by sieving then scarified and germinated. Seed bank density ranged between 640 and 2285 seedsm–2 with an average distribution of 82.7% and 17.3% in the upper and lower soil layer, respectively. Total density of the seed bank and also the seed bank ratio of the lower soil layer increased with tree age. The accumulated seed bank of R. pseudoacacia should be considered in the careful planning of tree replacement operations in Pinus nigra stands.


Keywords
Afforestation, dormancy, Pinus nigra, plantation, Robinia pseudoacacia, seed germination, soil seed bank

Batáry et al. (2012) Community Ecology

P. Batáry, A. Kovács-Hostyánszki, C. Fischer, T. Tscharntke & A. Holzschuh (2012): Contrasting effect of isolation of hedges from forests on farmland vs. woodland birds. Community Ecology 13(2): 155-161.

Abstract

Hedges and forest edges play a major role in providing nesting sites, food resources and shelter for birds in agricultural landscapes of western and central Europe. We investigated the response of farmland vs. woodland birds at two degrees of isolation of hedges from forest and to vegetation structure. We surveyed 200 m long sections of six forest edges, six hedges connected to forests and six isolated hedges. Species richness and abundance of farmland birds were higher in hedges than in forest edges, species richness and abundance of woodland birds were lower in hedges than in the forest edges. Species richness and abundance of both groups did not differ between connected and isolated hedges. Width and height of hedges and edges did not affect the species richness and abundance of either farmland or woodland birds. Furthermore, bird community composition differed between habitat types (hedge vs. forest edge) and also between hedge isolation levels (hedges connected to forest vs. isolated hedges). Based on our results, we emphasize the importance of hedges in conserving farmland birds and encourage policy makers to support hedge creation and maintenance with landscape-wide management strategies supporting a diverse hedge structure. Both connected and isolated hedges play an important role as they harbour different bird communities.

Keywords

Abundance, Community composition, Connectivity, Forest edge, Species richness

Møller et al. (2012) Oecologia

Anders Pape Møller, Mario Diaz, Einar Flensted-Jensen, Tomas Grim, Juan Diego Ibáñez-Álamo, Jukka Jokimäki, Raivo Mänd, Gábor Markó, Piotr Tryjanowski (2012): High urban population density of birds reflects their timing of urbanization. Oecologia 170(3): 867-875.

Abstract
Living organisms generally occur at the highest population density in the most suitable habitat. Therefore, invasion of and adaptation to novel habitats imply a gradual increase in population density, from that at or below what was found in the ancestral habitat to a density that may reach higher levels in the novel habitat following adaptation to that habitat. We tested this prediction of invasion biology by analyzing data on population density of breeding birds in their ancestral rural habitats and in matched nearby urban habitats that have been colonized recently across a continental latitudinal gradient. We estimated population density in the two types of habitats using extensive point census bird counts, and we obtained information on the year of urbanization when population density in urban habitats reached levels higher than that of the ancestral rural habitat from published records and estimates by experienced ornithologists. Both the difference in population density between urban and rural habitats and the year of urbanization were significantly repeatable when analyzing multiple populations of the same species across Europe. Population density was on average 30 % higher in urban than in rural habitats, although density reached as much as 100-fold higher in urban habitats in some species. Invasive urban bird species that colonized urban environments over a long period achieved the largest increases in population density compared to their ancestral rural habitats. This was independent of whether species were anciently or recently urbanized, providing a unique cross-validation of timing of urban invasions. These results suggest that successful invasion of urban habitats was associated with gradual adaptation to these habitats as shown by a significant increase in population density in urban habitats over time.


Keywords
Adaptation, Birds, Cross-validation, Invasion, Population density

Walker et al. (2012) Journal of Statistical Software

Steven C. Walker, Guillaume Guénard, Péter Sólymos, Pierre Legendre (2012): Multiple-Table Data in R with the multitable Package. 51 (8), http://www.jstatsoft.org/v51/i08/

Abstract
Data frames are integral to R. They provide a standard format for passing data to model-fitting and plotting functions, and this standard makes it easier for experienced users to learn new functions that accept data as a single data frame. Still, many data sets do not easily fit into a single data frame; data sets in ecology with a so-called fourth- corner problem provide important examples. Manipulating such inherently multiple-table data using several data frames can result in long and difficult-to-read workflows. We introduce the R multitable package to provide new data storage objects called data.list objects, which extend the data.frame concept to explicitly multiple-table settings. Like data frames, data lists are lists of variables stored as vectors; what is new is that these vectors have dimension attributes that make accessing and manipulating them easier. As data.list objects can be coerced to data.frame objects, they can be used with all R functions that accept an object that is coercible to a data.frame.

Keywords
data organization, ecology, fourth-corner problem, R